Fuse



Sept. l5, 1925 1,554,182

A. F. DAUM FUSE Filed Oct. 24, 1921 i6 l l 16k A m Z0 BM Patented Sept. 15, i925.

UNITED STATES PATENT OFFICE,

ALBERT F. DAUM, OF PITTSBURGH, PENNSYLVANIA; ROBERT E. DAUIVI, ADMINISTRA- TOR OF SAID ALBERT F. DAUIVI, DECEASED, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 DAUM FUSE AND ELECTRIC MANUFACTURING COMPANY, OF PITTSBURGH, PENN- SYLVANIA, A CORPORATION OF PENNSYLVANIA.

FUSE.

Application filed October 24, 1921.

T0 all whom t may concern.'

Be it known that I, ALBERT F. DAUM, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Fuses, of .which the following is a specification.

This invention relates to improvements in fuses, and pertains more particularly to constructions of the type in which the fusible element or elements can be readily replaced when the circuit has blown the fuse.

Various ways of meeting the problems of renewable fuses have been provided heretofore, the constructions dealing with the problems of construction or of installation or of manufacture in a number of different ways. In this respect the present invention is an'improvement in this general field, an improvement designed to provide for maximum efciency in operation, simplicity in construction, ease in substitution of fusible elements, readily manufactured, and capable of installation at low cost.

Primarily, the present invention has as its fundamental the use of an end closure for the tubular casing, said closure forming a support for the fusible element and anchoredr to the casing, with a cap having a skirt adapted to overlie the end of the casing but free from holding engagement therewith, said cap having means adapted to co-operate with the closure to secure the fusible element against movement, the cap having a form and a relation in the assembly such as to retain it out of contact with the fusible element.

In practice the end closure is provided with a kerf to receive the fusible element either by permitting it to pass therethrough or to form a space within which it may be received, the kerf being of a size to permit of the ready insertion of a fusible element of the proper thickness but insufficient to permit of the use of a thicker element of higher carrying capacity-thus tending to set up the conditions of preventing overloading of the fuse-the closure being arranged to permit the application of pressure on it in such manner as to tend to close the kerf, the walls of thel latter thus acting to not only retain the fusible element in position but also ensuring a close contact between the Serial No. 509,908.

closure and the fusible element for efficient service, especially under conditions where the invention is used in connection with fuses without blades.

If desired, the fusible element may be led through the end closure and extend alongside the blade and thus be brought into direct contact with the clips for receiving the fuse; and if desirable, either the closure, cap or closure-anchoring means, or all of them, may be of insulating material, so that the fuse-although of the blade type-may be entirely non-metallic in construction with the exception of the fusible element itself, the direct contact feature referred to permitting` this result to be obtained; where the blades are omitted, the cap forms the external terminal and the assembly should be metallic, although the closure-anchoring means may, if desired, be of insulating material or non-metallic. Y

The fuse is made up of a minimum number of parts. Aside from the fusible element-which is of strip form-the fuse, whether of bladed or non-bladed type, includes seven parts, the casing, the two enclosures, the two anchoring elements and the two caps; these may be of various forms, and in the preferred forms there are no tools needed to provide the refilling operation; an additional form carries two screws additional to the parts referred to, this form requiring the use of some screw-turning means to produce the clamping action.

More than a single fusible element may be employed, these extending preferably in parallelism, the additional fusible elements requiring no increase in'the number of parts over those required for the single fusible element.

The various parts are of forms such as to enable them to be readily manufactured at minimum cost, thus enabling the invention to be carried into practice at low cost, even where the fuse is of large capacity conditions.

To these and other ends, therefore, the nature of which will be readily understood as the invention is hereinafter more fully disclosed, said invention consists in the improved construction and combination of parts hereinafter more fully described, illustrated in the accompanying drawings and more particularly pointed out iii the appended claims.

ln the accompanying drawings, in which similar reference characters indicate similar parts in each of the vieWs,-

Figure 1 is a view, in longitudinal section, of a fuse of the bladed type, parts being broken away, the two ends being shown as having certain differences in material char'- acteristic.

Fig. 2 is an end elevation of a fuse of the er@ f f,l*`i-1` y Fig. 3 is 'an jnd vieiv yof 'an end closure.

Fig. t is an end vie'vvof a cap.

Fig. '5 is a transverse sectional view taken intern'iediatethe end closu'res.

Fig. 6 is a view generally similartoig. 1 showing vthe invention applie'd to Ia fuse of the non-bladed type.

Fig. 7v is a detail sectional View showing the end closure of a form to house the end of the fusible element.

Fig. 8 is a AView similar to Fig. a plurality of rfusible elements.

9 is a sectional view Slimme a slightly different arrangement of the means for clamping the fusible elementin position.

Fig. 10 is aV sectional vvieuv showing another arrangement for producing the clamping action.

ln each of the views, the tub ular 'casing, preferably o'f insulating material, is indicated at 15, the end-closure at 1o, the cap at 17, Vthe closureanchoring element at 18, and the fusible element at 19. `ln each form shown the casingissimilar, being p rovided with opposite openings 1 5a into which the ends of the element 'or member 18 extend, the latter being similar ineach form.

The end closure 16 is shown in various forms, but in eachtheinner portion 1651s of a size and foiin to: extend intothe open end of the casing and practically fit the saine, the closure having anfannula'r 'flange 1G" which over lies theend of Athe casing and of a size to preferably not vproject 'beyond the asing inthe peripheral cliiiiensioi'is of ca sing and closure. ln each ease, the closureanchoring means 18 extends 'through the inner portion 16?L offend closure 16 With the opposite ends of the means located inl openings 15a; as shown in Fig.` G, the means 18, shown as a pin, may extend parallel to the kerf 16 of the end closure or may extend transverse to the plane of and therefore intersectand pass through the'kerf 1GC and the portion'of the fusible element located therein.

Kerf 1 6 generally extends throughout the axial'length of the end closure, as in Fig. 1, for instance, the lrerf extending inwaid from one'side of the closure and terminating short of the opposite side so that the tivo portions of the end closure on opposite sides of the kerf are connected by the compara- 5 showing tively small connecting Aportion 16, the result being that these portions may be moved toward each other by applying pressure to either portion When the opposite portion is held `against movement. However, as shown in Fig. 7, the kerf may enter the end vclosure at the inner end and terminate short of the outer end of the closure-the connection 16d in suoli case being at the end instead of a side-the kerf, in such case, extending entirely across the inner portion 16a. For convenience in inserting the fusible element the entrance side of the kerf is preferably p`ro vided with a flared portion 16e located at least at the inner end of the closure, the flared Walls guiding the fusible element yto and into the kerf Without requiring lishing for the opening.

The kerf 16C, which may be provided vby sawing with a suitable sawiof prope'rdimensions, is preferably ofthe size to receive the fusible element with a loose'it, the Width of the lrerf being substantially the saine as the thickness of the fusible element istrip, the excess Width of lrerf being 'slightlsiniply suflicient to permit the entrance of the strip Without cramping. Thisarrangementserves to limit the size of the strip in cross-section and acts as a preventative to overloading, since a strip having a materially larger carrying capacit-y `will have aithickness suoli as to tend to expand the kerf and thus increase the size ofthe inner portion 16" to a point Where it will not enter Vthe casing. V ith theproper'size strip, the loose fit "Will permit ready entry 'and atthe same Atime permit the portions of the closure onopposit'e sides of the lreif yto be `moved inixfard relatively sufficient to clamp the strip "without straining the connecting portion 16d.

As a further means for preventing overloading by the' use of a strip of excess Width, especially yin the form inivhich'the connection is at the side, the connection 16d`ma'y have a Width such that the lerf 'Within' portion 16a has a length across the closure slightly'in excess of that required for the desired'strip, thus preventing the positioning of a strip of materially greater Width.

As slioivn in Fig. 8, the closure may have aplurality of lrerfs 16C, preferably soarranged that application of pressure on one side of the closure'ivill act to clamp eachl of a plurality of fusible elements .in position. One Way in which this can be done is illust'iated in this ligure, the lerfs being ranged vparallel with adjacent ylr'erfs extending from opposite sides of thefclosure.

As will be understood,members 18 'serve to anchor the closure to the casing, the result being that the ca p`17 need 'not art as the means for retaining the closure in position relative tothe casing, it being necessary only that the cap be held `sufficiently to prevent its falling off `when the assembly Lis completed, the skirt of the cap, when the latter is in position, overlying the ends of members 18 and preventing movement of the latter in a direction to permit removal of the closure 16; as a result, members 18 may have a loose tit to permit ready removal and positioning.

By eliminating the necessity of the cap to retain the assembly in position, it is possible to utilize the cap as a means for applying the pressure to the clamping portions of the closure, or as a carrier for such means. Various ways for obtaining this result are shown. For instance, in Fig. 9, the cap is Shown as provided with a set screw 20 at a point where it will, when threadid inwardly, apply pressure on to one of the clamping portions of the closure, and since the opposite clamping portion is held against movement through contact with the cap or the casing, or both, clamping action on the positioned fusible element will be had, the contact of screw and closure serving to sufficiently anchor the cap against moving outward; in Fig. 9, the cap is lshown as partially overlying the end of the casingan arrangement that may be employed with the remaining forms, if desired-but it is obvious that the cap, in this form may be of the type shown in Fig. 1, for instance.

Another way in which this result can be obtained is indicated in Fig. 10, wherein the closure 16 is shown as provided with a short thread Zone 16f-which may have one or more threadsthe outer end of the closure being shown as having a bevelled face 16g. In this form, the cap is provided with a similar Zone of internal thread formation, indicated at 17, and a bevelled face 17 b on the inturned flange 17c-the latter flange being common to each of the forms, the remaining forms, however, lacking the face 17". In this form, the cap is threaded to position, the bevelled faces 16g and 17b co-acting to produce the clamping action as the cap is threaded to position.

However, the preferred mode of securing the desired result is shown more particularly in Figs. 1 to 6, in which the cap and closure have faces relatively arranged in a manner to rset up a cam action therebetween when the cap is shifted in a rotative direction while in position on the casing. A simple way of obtaining this result is to offset the opening at the outer end of the cap, so that the inner peripheral face of flange 17 c will be eccentrically arranged with respect to the axis of the cap skirt, as in Fig. 4, the outer end of the closure having a portion similarly offset with respect to the axis of the closure to set up an eccentric relation of this portion-indicated at 16h with respect to the periphery of the inner portion 16a. In practice, I prefer to locate the cam portion 16h at the outer end of the closure and spaced from the end of casing 15 by an intervening portion of the closure arranged concentric to the closure axis and of a diameter to loosely fit within the cap skirt and therefore capable of cooperating with the cap in the clamping action; Fig. 3 indicates an approximate formation of such end portion 16h.

Obviously, when the closure is in position, the cap can be readily passed into position relative to the casing and the closure when theA eccentric portions have their axes in alinement-the diameters of the two eccentric portions varying slightly to set up a loose relation therebetween. Then in this position, the eccentric faces will be in cooperative relation, so that if the cap be moved in the direction of rotation, there will be a relative movement between the two faces 16h and 17C tending to bring the high side of the two faces into contact, and since the closure is held from being shifted to compensate for the change in relation-due to Contact of the diametrically opposite side of the inner portion 16"l with the casing* and the cap is likewise held from such shift through .its contact with the casing and the closure on such opposite side, it will be clear that such movement of the cap will apply pressure on that portion of the closure between such point of contact and the kerf, the result being that the closure is moved to clamp the fusible element in position, the friction developed between the cam faces retaining the cap in its position until released by a movement in the opposite direction. The parts are shown in clamped relation in Fig. 2. As will be clear this rotative movement of the cap can be readily had without changing the position of the cap in the direction of the fuse axis because of the fact that the cap has no holding engagement with the casing, so that the latter has a smooth exterior, the arrangement eliminating the threading of the casing, one of the factors of increased cost of fuses, this characteristic being present in each of the forms.

This arrangement is equally applicable for use in connection with fuses having blades and those without blades, Fig. 1 illustrating the former and Fig. 6 the latter. In the bladed type, the blade 16k is carried by the closure, either as an integral formation, as in Fig. 7 or at the right in Fig. 1, or as an inserted member as at the left in Fig. l; with the blade present, kerf 16C is preferably arranged parallel to the sides of the blade and in proximity thereto to permit the fusible element to extend outward and overlie one `side of the blade, as in Fig. 1, thus permitting the use of insulating material Afor one or more of the assnnbly members, as indicated at the right in Fig. 1- this end showing the cap, closure and closure anchoring means as of insulating material, the fusible element itself serving as the terminal coacting with the clips of the fuse block.

In the form shown in Fig. 6 lthe blades are omitted, the cap forming the terminal of the fuse, the fusible element extending to the end of the closure, as at the left in Fig. 6, or projecting beyond the end and folded over the exposed face of the closure, as shown at the right in such figure.

'In veither form, it will be readily understood that the exposure of the fusible element permits of inspection as to its crosssection and vthus enables check to be had on the character of fusible element employed in the fuse.

In the forms thus described the korf extends throughout the length of the closure 16, the connecting portion 16(1 being at a side of the closure and extending in the direction of length of the closure; in each of these the fusible element is exposed at the outer end of the closure. In Fig. 7, however, the lrerlf extends from side to side of -the closure, the connecting portion 16d* being located at the outer end and having its direction of length extending transverse to Ithe axis of the closure. This locates the end of the fusible element within what may be termed a poclet which, however, is open at opposite sides. To obtain the clamping action the closure is elongated as compared with the closure of the remaining forms to provide a portion which extends outward beyond ythe outer plane of the cap, ythe kerf Athus extending beyond the vplane at which the pressure is applied, so that the pressure-application will be made active on a section tof the closure capable of movement in the direction to clamp the fusible element.

The structure of Fig. 7 is shownas of the bladed type with metallic members in the assembly. As willbe obvious, `the blade may be omitted to produce a fuse of the type of Fig. 6; similarly, the assembly-parts may be of insulating material as at the right in lFig. 1. In addition, the closure may have avplurality of kerfs.arranged in parallelism as in Fig. 8, the connecting` portions, however,

being at the outer end of the closure. The clamping means may be as in Fig. 1 or as shown in Fig. 9.

- As will be understood, the opposite ends of the :fuse may have thesame assembly or the assemblies may be dissimilar, and this may be to the vextent of one end being bladed and the other free from ablade-a eombina tion of Figs. 1 and 6, for instance, such structure operating within clips adapted to receive the fuse of Fig. 6. And such dissimilarity may include the various forms shown in the drawings. And, as indicated in Fig. 6, Aan insulating washer 25 may be located onfthe fusibleelement inside the end closure, if it be desired to protect the metal of the end closures against the effects of arcing or to close up the exposed portions of the lrerf. However, the openings left by the kerfs when the fusible element is of less width than the kei-fs, is so small as to practically prevent the passage of flame therethrough and yet permit of the escape of gases when the fusible element blows.

For the purpose of readily distinguishing similar parts in the different forms shown, and to comply with the general rules relative to the use of reference characters, certain of the elements which have the same general action in all of the forms, Iare given varied lettering. The following will indicate these generally:

The end closure 16 is indicated in changed lettering, as follows: At the right of Fig. 1, it is indicated as 16'; in Figs. 2, 3 and 5, it is referred to as 16, but may obviously be of the material of 16. In Fig. 6 it is indicated as 116, in Fig. 7 as 16', in Fig. 8 as 16 in Fig'. 9 as 16 vand in Fig. 10

1G!! Ill The cap 17 is indicated at the right kin Fig. 1, as 17, in Figs. 2, 3 and il, it is indicated as 17, but may obviously be of the material of 17. In Fig. 9, itis indicated at 17, and in Fig. 10, it is indicated at 17 In the remaining figures the cap is indicated as 17 being similar to the cap at the left of Fig. 1.

The anchoring element 18 is indicated at the right of Fig. 1 as 18.

Thile I have 4herein shown and described various embodiments of my invention and various ways in which they may be combined for service conditions, it will be readily understood that changes and modifica tions 4therein may be found desirable or essential in meeting the exigencies of use, and I desire to be understood as vreserving the right Vto make any and all s'uch changes or modifications therein as may be found desirable or necessary, in so far as the same may fall within the-spirit and scope-of the invention as set forth in the lfollowingl claims when broadly construed, it being understood, of course, that the specific forms shown are more or :lessillustrativeof the general chau acteristics of such broad invention.

Having thus described my invention, what I claim as `new is:

1. In fuses, a tubular casing of insulating material, and means for supporting a fusible element Iof strip form to extend longitudinally ofthe casing, said means including an end closure anchored to the casing and havinga kerf adapted to receive a fusible element portion, and a cap removable from the closure and having its skirt overlyingthe end of the casing, said cap being free from holding engagement with the casing and carrying means `operative ito place the end closure in clamping relation with t-he fusibleI element portion located therein.

2. A fuse as in claim l characterized in that the end closure lrerf is normally of a width to provide a loose fit relation with a fusible element having a cross-section to provide the approximate maximum currentcarrying capacity condition for the fuse, such kerf width being insufficient to receive a fusible element of similar type but of materially greater cturent-carrying capacity and support such element in position within the fuse, the presence of an oversize element preventing clamping of the end closure.

3. A fuse as in claim l characterized in that theend closure and casing are relatively fitted to permit of ready location of a pertion of the closure within the casing when the fusible element and lrerf are relatively proportioned to permit ready entrance of the element into the lrerf prier to final assembly of the fuse, and prevent such location of the closure portion when a fusible element of similar type but of materially higher currentV carrying capacity is positioned within the kerf, the presence of an oversize element preventing clamping of the end closure.

il. A fuse as in claim l characterized in that the kerf is formed with an entrance of flared characteristic extending throughout the length of the end closure to permit of ready positioning of the fusible element within the kerf.

5. In fuses, a tubular open-ended casing of insulating material, and means for closing an end of the casing and form a support for a fusible element to extend longitudinally of the casing, said means including an end closure anchored to the casing and having a portion loosely fitted within the casing end and a portion overlying the end of the casing, said closure having a formation to loosely receive a fusible element portion, and a cap removable from the closure and having its slrirt in overlying relation to the end of the casing and free from holding engagement therewith, said cap having a portion in overlying relation to the portion of greater diameter of the closure, said cap carrying means operative to produce a clamping relation between the end closure and such fusible element portion.

6. A fuse as in claim 5 characterized in that the cap is formed with an inwardlyextending flange spaced from the end of the casing by the closure portion which it overlies.

7. In fuses, a tubular casing of insulating material, an end closure therefor and having a portion extending within the casing, said closure having a formation to support a fusible element portion to locate the fusible element longitudinally of the casing, means for anchoring the closure tothe casing, and a cap having its skirt overlying such casing end and the closure anchoring means and being free from holding engagement with the casing, said cap carrying means operative to produce a clamping relation between the end closure and such fusible element portion.

8. In fuses, a tubular casing of insulating material, an end closure therefor, said closure having a kei-f extending from end to end of the ciosure, said lrerf being` adapted to receive a fusible element p rtion and extending transversely of the closure and of a length in such transverse direction less than the length of the closure in such direction and with one kerf limit of such transverse length .located at the periphery of such closure to provide closure portions free to move toward one another, said closure being anchored to the casing, and a cap having its skirt in overlying relation to the casing and free from holding engagement therewith, said cap carrying means operative to produce relative movement between such closure portions to clamp the fusible element portion in position.

9. A fuse as in claim 8 characterized in that tie end closure carries a blade, the kerf being positioned relatively to a face of the blade in such manner that another portion of the fusible element will entend in overlying relation to such blade face when bothy portions of the fusible element extend in the same plane.

10. In fuses, a tubular casing of insulating material, and means for supporting a fusible element to extendr longitudinally of the casing, said means including a closure anchored to the casing and having a formation to support a fusible element portion, and a cap having its skirt in overlying relation to the casing end and free from holding engagement with such end, said cap and closure having complemental means operative to produce a clamping relation between the closure and such fusible element portion.

l1. In fuses, a tubular casing of insulating material, and means for supporting a fusible element to extend longitudinally of the casing, said means including an assembly of end closure and cap with the end closure adapted to support a fusible element portion7 and with the cap and end closure extending on opposite sides of a wall of the casing, said cap and closure being relatively formed to permit positioning of the cap when the closure is in position and to produce a clamping relation between the closure and fusible element portion by rotative movement of the positioned cap in a single plane.

l2. In fuses, a tubular casing of insulating material, and means for supporting a fusible element to extend longitudinally of the casing, said means including an assembly of end closure and cap with the end closure adapted to support a fusible element portion, and with the cap and end closure extending on opposite sides of a wall of the easing, said cap and closure being relatively formed to permit positioning of the cap when the closure is in position and to produce a clamping or releasing relation between the closure and fusible element portion by rotative movement of the positioned cap in the same plane.

13. In fuses, a tubular casing of insulating material, and means for supporting a fusible element to extend longitudinally of the casing, said means including an assembly of end closure and cap with the end closure adapted to support a fusible element portion, and with the cap and end closure extending on o-pposite sides of a wall of the casing, said cap and closure having complemcntal means operative to produce a clamping relation between the closure and fusible element portion by rotative movement of the cap in a single plane.

14;. A fuse as in claim 13 chaiacterized in that the complement-al means provide cooperating faces having characteristics of a cam when the capv is rotated.

15. In fuses, a tubular casing of insulating material, and. means for supporting a fusible element to extend longitudinal-ly of the casing, said means including an assembly of end closure and cap with the closure anchored to the casing and adapted to support a fusible element portion, and with the cap and closure extending' on opposite sides of a Wall of the casing, said closure having a curved face the axis of which is out of alinement with the axis of the closure, said cap having a face adapted to co-operate with the closure face to apply lateral pressure to the closure when the cap is positioned and rotated in a single plane.

16. In fuses, a tubular casing of insulating material, and means for supporting a fusible element to extend longitudinally of the casing, said means including an assembly of end closure and cap, with the closure anchored to the casing and adapted to support a fusible element portion, and with the cap and closure extending on opposite sides of a wall of the casing, said cap and closure each. having a. circular face located to oppose each other in the assembly, with the axis of each face out of alincment with the axis of the part which carries the face, said faces, in one position of the cap being in concentric relation to each other, movement of the cap rotatively being operative' to produce' an eccentric relation between the faces and produce a camming action therebetween.

17. A fuse as in claim 16 characterized in that the cap movement rotatively is in a single plane-` 18. A fuse as in claim 16 characterized in that the radius of the closure face is slightly less than the radius of the cap face'.

19. A fuse as in claim 16 characterized in that the cap face is carried by an' annular flange projecting inwardly from the skirt of the cap and adapted to overlie a portion of the closure positioned between the closure face and the end of the casing in the assembly.

ALBERT F. BAUM4 

